Unmanned aircraft



FIG. 1 is a perspective view of the aircraft looking downward from the front;

FIG. 2 is a front view of the aircraft;

FIG. 3 is a rear view of the aircraft;

FIG. 4 is a top view of the aircraft;

FIG. 5 is a bottom view of the aircraft; and,

FIG. 6 is a side view of the aircraft. 

The ornamental design for an unmanned aircraft, as shown. 